I never, ever try to weasel upgrades. I'm one of those people who feel really embarrassed about wheedling. I never haggle over price. I sort of wander away out of shame when someone does that. I'm socially nonfunctional in those situations.
I don't get jet lag as long as I get my sleep. As tempting as it is to get really drunk on the plane, I avoid that. If you take a long flight and get off hungover and dehydrated, it's a bad way to be. I'll usually get on the plane, take a sleeping pill, and sleep through the whole flight. Then I'll land and whatever's necessary for me to sleep at bedtime in the new time zone, I'll do that.
There's almost never a good reason to eat on a plane. You'll never feel better after airplane food than before it. I don't understand people who will accept every single meal on a long flight. I'm convinced it's about breaking up the boredom. You're much better off avoiding it. Much better to show up in a new place and be hungry and eat at even a little street stall than arrive gassy and bloated, full, flatulent, hungover. So I just avoid airplane food. It's in no way helpful.